The present invention relates to a type of gaming machine which is commonly referred to as a slot machine. More particularly, the present invention relates to an electronic slot machine which allows players to select for respin one or more of the symbols displayed after the machine""s first spin. This feature allows the player to get a second chance at creating, improving or even losing a winning combination.
Over the years, many games of chance have been devised to allow players to wager a sum of money and have the opportunity to win greater sums of money. Such games include lotteries, bingo, keno, blackjack, poker, roulette, craps and slot machines.
Of these games, many people find slot machines to be the most entertaining. In a basic mechanical slot machine, the player inserts a bill or coin and pulls down on the slot machine handle to initiate the game. Three parallel, rotatable reels with an assortment of fruit, number and/or bar symbols are then caused to spin until each reel reaches a resting position. The success or failure of the game is then determined by comparing the combination of reel symbols across a horizontal row with a table of winning combinations posted on the slot machine. To add interest to the game, the basic mechanical slot machine windows are frequently made large enough to show three adjacent symbols on each reel and thereby allow betting involving multiple rows. This betting can take the form, for example, of betting on the combinations formed across the upper horizontal row, middle horizontal row and lower horizontal row. Betting along diagonal lines intersecting these rows is also made possible. Because the combination of symbols on each reel of a basic mechanical slot machine is fixed, there is typically no betting on vertical column combinations in the basic mechanical slot machine.
With the advent of electronic technology, there have been many improvements to the basic slot machine. Among these improvements are the use of video monitors to display an imitation of three parallel, rotatable reels, rather than having three actual reels themselves. In operation, these electronic slot machines simulate the rotation of a physical reel, but typically select the final symbols through use of random numbers generated by a microprocessor rather than any physical rotation of a reel. In other words, the final symbols for each simulated reel in the electronic slot machine are randomly selected by the microprocessor and then displayed on the video monitor at the appropriate time and position.
The use of electronic technology for slot machines has allowed additional improvements to slot machine play. For example, the number of combinations that can be displayed on a video monitor is no longer limited by the number of symbols that can be fit onto three physical reels. This opportunity for greater numbers of displayed combinations has led the way to greater jackpots and progressive slot machines. Also, with electronic technology, the three symbols shown in each column no longer need to correspond to three adjacent symbols on a physical reel. Through generation of different random numbers, each symbol displayed in a video monitor column can be independently generated. By independently generating each of the symbols shown on the video monitor, betting along vertical columns as well as horizontal rows and diagonal lines has now become feasible.
One frequent frustration that players have with slot machines, even the new electronic slot machines, is that the combination which is finally displayed along their betting line may fall just short of a winning combination and the player has no opportunity for adjusting the displayed combination, short of completely starting a new game. To address this frustration, some mechanical slot machines allow a player to xe2x80x9cnudgexe2x80x9d one of the reels so that the displayed symbol is moved one notch and replaced by an adjacent symbol on the reel which is visible to the player. The success or failure of the game is then redetermined based upon the combination appearing after one of the reels has been xe2x80x9cnudged.xe2x80x9d
While the xe2x80x9cnudgingxe2x80x9d feature does help overcome some of the frustration of being one symbol short of a winning combination, it provides only limited relief. For example, if the next symbol on the particular reel will not create a winning combination, then there is no reason to xe2x80x9cnudgexe2x80x9d and have that next symbol included in the displayed combination. Also, to the extent the symbol to be nudged into place is visible, it is fairly obvious to the player whether or not to nudge. For this reason, use of a xe2x80x9cnudgingxe2x80x9d feature adds very little additional interest to the game and, moreover, is unlikely to allow such slot machines to be reclassified from a game of xe2x80x9cchancexe2x80x9d to a game of xe2x80x9cskillxe2x80x9d in those jurisdictions which prohibit games of xe2x80x9cchance.xe2x80x9d
The present invention provides an electronic slot machine which allows a player to completely respin one or more of the symbols displayed after the first spin in order to create, improve or even lose a winning combination. In its preferred form, the electronic slot machine of the present invention features a video monitor with a plurality of symbol display boxes arrayed in rows and columns. When the machine is activated through, for example, insertion of a valid coin and pressing of the xe2x80x9cspinxe2x80x9d button, one or more random numbers are generated in the slot machine""s microprocessor and compared to one or more reel strips encoded in computer memory to determine which symbols are to be displayed in each of the symbol display boxes. If a desirable winning combination is not formed after this first spin, the player is given an opportunity to select one or more of the symbol display boxes, rows of symbol display boxes or columns of symbol display boxes for respin. Where a touchscreen is used in conjunction with the video monitor, the player can make this selection simply by touching the boxes, rows of boxes or columns of boxes to be respun. After an appropriate number of boxes are chosen for respin, one or more additional random numbers are generated and compared with reel strips encoded in the computer memory to determine which new symbols are to be displayed in each of the selected boxes. After the new symbols are displayed in the selected boxes, the microprocessor compares the displayed symbols with a memorized list of winning combinations to determine if the game is a winner. If a winning combination is formed, the microprocessor determines the appropriate payout for the winning combination and provides the player with that payout.
There are, of course, numerous respin options that are enabled by the apparatus of the present invention. For example, if a symbol after the first repin turns out to be the same as the original symbol, that symbol can be respun again, either automatically or at the player""s option, in order to try to obtain a different symbol. Alternatively, having the same symbol appear again after a respin could be used as an opportunity for allowing the player to have a second chance to respin any of the other symbols. As a second alternative, color backgrounds could be added to each of the symbol boxes and serve as an additional criteria for respinning to achieve winning combinations.